THE ORGAN AND SENSE OF TASTE IN FISHES. 
261 
I next took small clam shells that had been lying long in the tanks containing 
the fish and were, thoroughly cleaned of fleshy matter and which the fishes had not 
paid any attention to for days. These 1 dried and warmed and then filled 
with melted gelatin which had been previously softened up in cold water. Upon 
cooling there results a mass, colorless, tasteless, and odorless, which feels almost 
exactly like the flesh of the clam, which has often been fed to the fishes in this way. 
Upon dropping these shells into the water, the fishes eagerly snatch them up, feel of 
them with the lips or barblet, and then bite into the gelatin. They immediately 
reject the gelatin and they never repeat the process. Even if they draw the fins or 
barblets repeatedly over the shells and the contained gelatin, they never again pay 
any attention to them. 
1 also repeated with the hake the experiments which 1 had previously carried 
out upon the cat-fish, using a fine-pointed pipette and sapid solutions. The fishes 
were in all cases first tested with sea water taken from the tank in which they were 
swimming. • On one occasion (the first test made) a jet of water directed against the 
filamentous dorsal was followed by the characteristic backward movement of the 
fish, so that he finally received the jet in the face. He turned and tried to take the 
point of the pipette in his mouth — a purely tactile reflex apparently. This response 
1 never got again with this or any other fish, though occasionally the fish would 
stop, hesitate a moment, and then swim on, paying no further attention to the 
stimulus. If the jet of water is directed against the pelvic fin while it is extended 
and searching the bottom for food, the fin is usually quickly withdrawn and pressed 
against the side of the body. 
The pipette was then filled with the freshly prepared and strained juice of the 
mussel ( Modiola ), and this was directed against the fish in the same way. The fishes 
responded instantly, just as when stimulated by meat, whether the jet was directed 
against the filamentous dorsal, or the dorsal fin at any part, or the side of the body, 
or the free pelvic fin. The reflex is immediate and unmistakable, more sharply 
defined than I usually get by contact with the meat of the same mussel. The experi- 
ment, was many times repeated, always with the result that the jet of water was 
ignored or avoided, while the jet of mussel or clam or crab juice was eagerly sought, 
the fish usually snapping - at the end of the pipette. 
I have carried out no systematic chemical experiments to determine the gustatory 
preferences of the fishes, having shaped my experiments so far as possible along the 
lines of the normal feeding habits of the species studied. Nagel and some other 
previous students of these problems have relied chiefly on reactions to unpleasant 
stimuli, and the reader is referred to their works, though I consider this a less satis- 
factory line of inquiry than the study of normal reactions to food substances. The 
few fragmentary observations which 1 have made with chemical stimulants I shall, 
however, record in their appropriate places. 
Specimens of hake were tested with a 0.2 per cent solution of hydrochloric acid 
made up in distilled water, the acid being directed against the body by means of a 
fine pipette. The dorsal and ventral fins, the sides of the body, and the lips were 
tested. When first tested on the fins one hake turned and tried to take the pipette, 
much as he did with the clam juice. Afterwards this fish, as well as all the others 
from the first, seemed rather to dislike the acid and would swim slowly away. There 
